Fuel injection means for motors



Dec. 14, 1 937. o. L. A. RIEGELS FUEL INJECTION MEANS FOR MOTORS FiledApril 26, 1935 2 Sheets-Sheet l INVENTOR CILAP LARIEEELE.

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ATTORNEY Patented Dec. 14, 1937 UNITED STATES PAT'ENT' OFFICE ()lafLeonhard Augustinus RiegelslfCleveland,

. Ohio Application April 26,

Claims.

This invention relates to fuel oil injection means for direct'injectionoil engines or motors, and has particularly reference to those of theDiesel type.

5 Because of very pronounced pressure fluctuations occurring in the'fuelline during fuel injection, a constant and gradual injection of fuel oilcannot be obtained under present practice in this art; and because ofthe extremely low compressibility of the fuel oil and the high rigidityofthe enclosing structure, the time-interval of the pressurefluctuations is very short, and accordingly a number of suchfluctuations :take place in the time necessary for and during a singlegradual injection of the fuel. One object'of this invention is to reduceor eliminate these fluctuations.

In an injection apparatus or nozzle and in the fuel line of a Dieselengine, two kinds of fluctua- 2 tions or waves are ordinarily observedand known to exist. One kind originates at the fuel pump,

due to the compression of the fuel and exists in the fuel line and inthe injection nozzle, when the latter is closed by the nozzle valve.These n fluctuations are known as and have the character of pressurewaves, but they are not important as they have a relatively lowfrequency and their tion valve, fluctuations or waves are built up,

which travel from the nozzle tip to the end of fuel supply pipe or pumpplunger and back and forth again. These waves have the character ofrarefaction or tension waves and are very violent and cause at theirmaximum amplitude a considerable pressure drop, which reduces thepressure to an amount much less than is necessary 43 to sustain acontinuous and gradual injection.

If said tension waves are damped out or balanced by pressure waves ofequivalent frequency and intensity and opposite phase, a.continuous andgradual fuel injection results.

is, according to the present embodiment, accomplished by a stop orbypass valve placed in a bypass opening and operated by elementsco-acting with the nozzle valve, to move oppositely with respectthereto,so as to effect a closure of the one as the other is opening.Accordingly, another This action 1935, Serial No. 18,395

Another object of the invention is to provide.

Another object of the invention is to construct an improved fuelinjection nozzle having a stop valve provided with a removable valveseat.

A further object of this invention is to provide an improved fuelinjection means having an injection valve and a stop valve the openingsof which are of predetermined correlated size to insure a balanced wavere-action during fuel injection.

. Other objects of the invention will be apparent to those skilled inthe art towhich my invention relates from the following descriptiontaken in connection with the accompanying drawings, wherein Fig. 1 is aview, partly in elevation and partly in section, of anengine'embodying-my invention.

Fig. 2 is a fragmentary section of parts shown in Fig. 1, enlargedv Fig.3 is a sectional view of the fuel pump, enlarged.

Fig. 4is a view of parts shown in Figs. 1 and 2, slightly modified andpartly diagrammatic.

Fig. 5 is a diagram.

In the drawings, A indicates as an entirety an engine of the Dieseltype, showing one cylinder B and a piston C therein. The engine may beconstructed to provide any number of cylinders, as

desired, but as my improved injection means is applied to each cylinder,only one thereof need be illustrated and referred to. D indicates apiston rod, which drives a crank shaft E. The shaft E is drivinglyconnected to a cam shaft F which, through' the rod f and rocker 1, timecontrols the usual exhaust valve to the exhaust manifold G. H indicates,the fuel pump having a fuel inlet h connected with a pipe leading from asuitable soiu'ce of supply and a fuel outlet 71. connected to a conduit,1. "The shaft 1' of the.pump is suitably driven, for example. by thegearing shown in Fig. l, to rotate a cam which'in turn, in cooperationwith a spring, operates the pump plunger i. The pump H serves to supplythe fuel. to the injection nozzle, as hereinafter set forth, atrelatively high pressure. Any desired construction of pump for thispurpose may be used, that shown being for illustrative purposes only. aindicates a casing formed integrally with the "cylinder head a" andshapedto form axially of the cylinder B a tubular wall I), enlarged atits upper end, to receive and support the injection valve'nozzlestructure, the head a being formed with an opening b axially of thecylinder to receive a portion of the structure, as later described.

I indicates a hollow body member of the injection valve having a mainportion la, an integral neck portion lb at its lower end (these portionsbeing seated in the wall b) and an integral head is at its upper end.The lower end of the neck portion lb is preferably of conical shape towhich is axially related a removable, tubular tip member 2 removablyfitting at its lower end into the opening b, and having at such end anend wall formed with a nozzle opening 20,. The inner wall of the tipmember adjacent its end wall is cut away to form a chamber 2a:. Theupper end of the opening 2a is of conical shape to form the valve seat20. of the movable injection valve element 3 to be later referred to.The tip member 2 is reduced in diameter throughout a portion of itslength to form a shoulder 2', which is engaged by a shoulder on asleeve'2c, the upper end of which is'threaded on the lower end of theneck portion lb to removably secure the tip member in position. The headI 0, main body portion Ia, neck portion lb and tip member 2 are formedwith ducts in connected relation to provide a fuel supply conduit 4suitably connected at its upper end with the conduit I and leading tothe chamber 2.1:5'also these parts are formed with ducts in connectedrelation to provide a fuel conduit 5 leading from the chamber 21: to anoutlet 6, connected to a pipe 1, which leads to the fuel supply orstorage tank (not shown). A stop valve 8 is providedin the conduit 5,forming a valve controlled bypass, for a purpose later set forth.

The injection opening through the tip member 2, located between thevalve seat 2a and the engine cylinder, is accurately sized to permit thepassage therethrough of exactly the desired amount of fuel required bythe particular engine to which the injection valve is applied when thevalve element 3 is moved from its seat to give free flow of fuel fromthe pressure feed line I to the engine cylinder.

The shank 3a of the injection valve 3 slidably extends through the necklb and an opening in a plug 9 threaded in the upper end of the mainportion la, the upper end of the shank 3a being threaded to adjustablysupport a cap I0, which is engaged by one arm of a rocker H suitablyfulcrumed on a standard I2. The plug 9 serves as an abutment for one endof an expansion spring I3 coiled around the shank 3a, the other end ofthe spring engaging a collar [4 fixed to the shank and normally actingto seat the valve 3 against its seat. The plug 9 is positioned in thebody portion la. so as to adjust the tension of the spring to thepredetermined pressure desired to effect or permit opening of theinjection valve 3. The lower end portion of the shank 3a is reduced toform an annular shoulder 3 against which the fuel pressure acts tounseat the valve 3.

The stop valve 8 comprises a seat member 8a removably mounted in anopening formed in the head lo and a plunger 8b, the lower end of whichforms the valve element to engage the seat member. The opening throughthe seat member communicates with the adjacent ducts of the conduit 5.The upper end of the opening in the seat member 8a is of conicalshape toform the seat for the similarly shaped lower end of the plunger 8b. Theplunger slidably fits an opening formed in a plug l5 threaded'into anopening formed in the head lo, the upper end of the plunger 8b beingarranged to be engaged by the other arm of the'rocker H. The upper endof the plug I5 is provided with a boss to which a split collar l6, whichis connected to the standard I2, is suitably clamped. As the rocker llengages the plunger 8b and shank 3a, the injection valve 3 is closedwhen the stop valve 8 is opened, and when the valve 3 is opened, valve 8is closed.

Fuel supplied under pressure by the pump H flows through the conduit 4to the injection valve 3 and if the latter is closed, the fuel flowsthrough the conduit 5 to the return pipe 1, the pressure of fuel servingto lift the plunger 8b and permit such fuel flow to the pipe 1. Thisfuel fiow per mits air contained in the fuel line to escape and thosepressure waves originating at the pump and caused thereby during thisstage of opera tion to be eliminated so long as the injection nozzlevalve remains closed. As soon as the pressure of the fuel rises to apoint sufi'icient to overcome the pressure of the spring l3 (whichspring pressure is adjusted to a predetermined tension dependent uponthe area bf the valve 3) the resulting fuel pressure acting on theshoulder 3, which has an area larger than that of the valve element 3,will lift the valve element 3 from its seat, permitting the injection ofthe fuel into the combustion chamber or cylinder.

Because of the low pressure in this chamber, compared with the highpressure of the fuel, the

fuel will tend to regain its original or normalv density and volume, inproportion to said pressure difference, resulting in a sudden pressuredrop in the injection nozzle, and as the compressibility of fuel oil isvery low, and said pressure difference is very high, this sudden drop inpressure creates a tension or rarefaction wave,

which travels from the injection nozzle tip to the pump or pressuresource and back and forth. As the time period of these waves is veryshort compared with the time of injection for Diesel cycle operations,these waves or fluctuations, of which a plurality occur during eachinjection, prevent gradual fuel injection.

When the injection valve 3 lifts, it operates the rocker which in turncloses the stop valve to stop the flow of fuel through the conduit 5,the effect of which, due to the sudden check in the velocity of thefuel, is to cause a pressure wave of equal frequency and of oppositephase to that of the tension wave and traveling from the stop valve tothe pump and back and forth. These tension and pressure waves justreferred to havepractically the same period (the difference between themin this respect being so slight as to be immeasurable and hence may bedisregarded) and if their amplitudes be the same they may be caused toneutralize or damp out each other so that they have nopractical effectin the injection nozzle, with the result that a grad-- nail andcontinuous injection of fuel into the combustion chamber takes place.

To secure this wave balancing eifect in order to insure a smooth flow offuel into the engine cylinder it is especially important that the wavesof force of opposite phase,-the tension waves originating at theinjection valve and the pressure waves originating at the by-pass orstop valve,-shall accurately oppose each other, as distinguished frombeing in more or less staggered or out of step relationship, as has beenthe case in earlier attempts to obliterate these waves of force whichinterfere with proper fuel feed. I have discovered that this accurateharmonic opposing of these waves of opposite phase may be accomplishedby properly operating the injection and the by-pass or stop valves withrelation one to the other. Thus theinjection valve is so operated thatits discharge passage 2b into .ceedingly short movement of the valvestem 3 at the beginning of the movement of the valves insures this fullfuel feed opening,further movement of the valve stem 3 not affecting theopening or size of the fuel passage 2b. On the other hand the movementof the stop or by-pass valve must be gradual in its control of the flowof fuel through passage l8, this being insured by operating this valveso as to much prolong its flow-restricting or accelerating movements;for, as will be seen by reference to Figure 4 when the valve stem 8moves with reference to the seat 8a the flow passage to.the port I8 isgradually varied in size by reason of the relatively long taper at theend of the stem.

I not only secure this accurate positioning in harmonic opposition ofthe waves of opposite phase, but I cause such opposing waves to be. ofequal force so they counter-balance each other, thus losing theirinterfering effects upon the flow of fuel which passes on into theengine cylinder as a smooth, steady stream. To insure this latter resultI co-ordinate the discharge apertures in the two valves as to theirsizes or areas in proportion to the differences in pressure on thedelivery sides of the two valves.

It is evident that the flow of fuel through the injection valve is fromthe fuel line where the pressure is high,let it be assumed 4000 lbs. per

sq. in.,-into the engine cylinder where the pressure is muchlower,-perhaps 500 lbs.; and that at the stop valve the flow is from thehigh pressure fuel line into the return pipe where the pressure may beatmospheric or thereabouts. Thus there is a very considerable differencein the pressures of the fluid passing the two valves respectively; and,since the volume of fuel passing the port or opening of a valve isgoverned both by the difference in the pressure of the fuel on the twosides of the valve, and the size of the port throughwhich it is flowing,it becomes necessary, in order to secure the desired results in thecounterbalancin'g, and neutralizing of the effects of the waves of forcetraveling through the pressure column of liquid when the valves areoperated, as has been described, that there be uniform volumetric flowthrough the two valves when they are operated. I have discovered thatdue to the facts just stated the fuel passage through the stop valvemust be slightly smaller than the corresponding passage through the fuelinjection valve, as they are simultaneously operated, to effect thisdesired result and insure a uniform delivery of fuel to the injectionnozzle.

To insure accuracy, the mounting for the rocker Il may be adjustedlaterally the effect of which is to change the length of the rocker armsrelative to the points of contact with the shanks of the valveelements.- This adjustment is'preferably provided for by an eccentricll" having an extended end (not shown) to permit its operation andsuitable means for securing it in operated position. In connection withsuch adjustment, the cap Ill may be adjusted to provide the accuraterelationship between the valves; also the plunger for valve 8 may beprovided with an adjustable cap, similar to cap l0, if found'to bedesirable.

If a wider seat for valve 3 is needed, for ex- I ample where a multiplehole nozzle tip or a pintle type-of nozzle valve is used I can eitherprovide the proper size seat openings by the use of correspondinglydifferent valve seat angles, or by a combination with different rockerarm lengths as described, or I can use equal valve seat diameters incombination with equal discharge openings.

Fig. 4 shows a valve head arrangement embodying the several features ofmy invention. Referring to this view it will be seen that the injectionafull 0pening of the engine cylinder injection v passage, while afurther movement of the valve stem has no effect on the size of suchpassage. On the other hand the taper of the by-pass valve stem 8 islonger and more gradual than that of V the stem 3 with the result thatthe change in the size of passagebetween the seat 80. and the taper ofthe valve stem 8 takes place throughout the full movement of thestem,from full open to completely closed position and vice versa,--sothat the starting of the operation of the by-pass valve,- either to openor to close-is synchronous with the simultaneous movements of the twovalves.

From the foregoing description it also will be understood, that a changeof type of the injection valve 3, or the slightest change of the amountof discharge through said valve, will call for an equivalent change ofthe character of the stop valve 8 and its discharge opening. To permitof change in the seat of the stop valve, I provide its seat in an insertmember 8a, which is readily accessible and removable and is constructedto have the discharge passage l3, of the proper size such as has beendescribed, located at such distance from'the seat 8a with which thetapering valve stem 8 cooperates as permits the gradual closing andopening movements of the valve as has been .pointed out.

cated at 39, 39a, 39b, etc. represent the time period of the tensionwaves and pressure waves.

When the injection nozzle 3 starts to unseat at point 40, the compressedfuel rushes out, represented by line 49, trying to accelerate to avelocity of full flow at line 31, but before it reaches this point itexpands to its normal density which results in a sudden pressure drop,which maximum at point 4| will occur in the time interval represented by39, and immediately surge up again to a maximum pressure at 42, followedby a maximum drop again to point 43, which action will be repeated inthe character of tension waves, and having a constant time period frompoint 40 to 4|, from 4| to 43, etc. represented by the constant equallength of lines 39, 39a, 39!), etc.

As these fluctuations under practical conditions are repeated severaltimes in the duration of each injection, represented by the length ofline 38, a gradual or uniformly smooth injection has hither-v to beenimpossible. But, when the injection valve and operating conditions.

3 starts to-unseat the stop valve 8 simultaneously starts to close, andas the momentum of the suddenly stopped fuel column in conduit 5 isequal to the momentum of the fuel column in conduit 4 suddenly releasedby valve 3, a pressure wave 44 is originated, which maximum pressure isreached at point 45 having precisely the same frequency and intensityand of opposite phase as the tension wave 49, and thus the forces arebalanced as described. The pressure rise represented by the length ofthe line 41, will precisely balance the pressure drop represented by theline 46. As all of the following pairs of pressure and tension waveswill likewise become balanced, an effective pressure, represented by theline 48, will result in a controlled constant and gradual injectionpractically free from fluctuations.

It will be observed that the tip or valve seat member 2 of the injectionvalve, and the seat member 8a of the stop valve, are both relativelysimple parts and are arranged and mounted so as to be easily removableand replaceable without disturbing the other parts of the entire valveassemblies. The purpose of this arrangement is this: in practice the twovalve assemblies-the injection valve and the stop valve--arestandardized so as to be fitted to engines of varying sizes But for eachdifferent size of engine and for engines of the same size whereoperating conditions are Widely difierent, the flow of fuel past the twovalves must be determined and the flow in the separate valves accuratelyrelated one to the other in order that the discharge of fuel into theengine cylinder shall be steady and uninfluenced by the periodicallyrecurring fluctuations in pressure which take place in the vicinity ofboth of the valves, and due to their movements, whenever they areoperated. This adjustment of the valves to suit sp'ecial sizes andconditions of engines is determined by theoretical calculation, or trialand test for the particular engine in question, or by a combination ofthese methods of determination as to the proper parts to be used. Theselatter being determined upon may be easily inserted into their properpositions in the engine without disturbing the other parts of the valveassemblies.

To those skilled in the art to which my invention relates, many changesin construction and widely differing embodiments and applications of theinvention will suggest themselves without departing from the spirit andscope of the invention. My disclosures and the description herein arepurely illustrative and not intended to be in any sense limiting.

What I claim is: l

1. A fuel injection apparatus for internal combustion engines, whichincludes a source of fuel supply under high pressure, a normally closedspring-controlled injection means comprising a valve seat having adischarge opening of predetermined size governed by the desireddischarges into the engine cylinder, and a movable element co-operatingwith such valve seat, a bypass means for periodically by-passing fuel tosaid source of supply and comprising a valve seat having adischargeopening and a movable valve element cooperating with said seat,the related surfaces of said last mentioned valve seat and valve elementserving gradually to open or close the discharge opening through thevalve seat during the movement of said valve element, the dischargeopening through said last mentioned valve seat being smallerthan thedischarge opening through said injection means valve seat and saidopenings being proportioned to the relative pressures respectivelybeyond the same, the higher pressure being beyond the injection valvewhere it discharges into the engine cylinder, and means for operatingsaid movable valve elements for effecting the opening of one valvesimultaneously with the closing of the other, said means beingco-ordinated with the relative sizes of said discharge openings toinsure equal volumetric flow through said openings.

2. An apparatus such as described in claim 1, wherein the valveoperating means comprise a rocker engaging the valve elements of saidvalves arranged to close one valve when the other is opened, the arms ofsaid rocker being related to the relative sizes of the openings for saidvalves to provide for the same volumetric discharge of fuel through onewhen open as through the other when the latter is open.

3. An apparatus such as described in claim 1, wherein the valveoperating means comprise a rocker engaging the valve elements of saidvalves arranged to close one valve when the other is opened, the arms ofsaid rocker being related to the relative sizes of the openings for saidvalves to provide for the same volumetric discharge of fuel through onewhen open as through the other when the latter is open, and means foradjusting the fulcrum for said rocker.

4. An apparatus as claimed in claim 1 wherein the movement of the valveelement of the injection valve away from its seat by the operating Imeans terminates when the valve element of the by-pass valve closes itsvalve, and the movement of the valve element of the by-pass valve awayfrom its seat by the operating means terminates when the valve elementof the injection valve closes its valve.

5. The herein described method of operating an internal combustionengine of the Diesel type, wherein is employed a feed system of fuelunder pressure, including a source of supply, a fuel line to an enginecylinder, a return line to the source of supply and a normally closedinjection valve in the fuel supply line, which method consists inoperating the injection valve, in synchronized relation to thecompression stroke of the engine piston, through a predetermined cycleand causing an opening of its injection port to provide a predeterminedvolume flow of fuel in the initial portion of the cycle, maintainingsuch opening through an intermediate portion of the cycle and finallyclosing the injection port in the latter portion of the cycle wherebytension Waves are set'up in the fuel, and simultaneously in the returnline beyond the injection valve and during and throughout the completecycle of movement of the latter valve, checking the flow of fuel througha port of smaller area than the port of the injection valve to set uppressure Waves which are of opposite phase to the tension waves andcontrolling the pressure waves so that they start at the time theinjection valve starts to open and are stopped at the time the injectionvalve closes.

OLAF LEQNHARD AUGUSTINUS RIEGELS.

